Scientific Reports (Feb 2024)

A large therian mammal from the Late Cretaceous of South America

  • Nicolás R. Chimento,
  • Federico L. Agnolín,
  • Jordi García-Marsà,
  • Makoto Manabe,
  • Takanobu Tsuihiji,
  • Fernando E. Novas

DOI
https://doi.org/10.1038/s41598-024-53156-3
Journal volume & issue
Vol. 14, no. 1
pp. 1 – 8

Abstract

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Abstract Theria represent an extant clade that comprises placental and marsupial mammals. Here we report on the discovery of a new Late Cretaceous mammal from southern Patagonia, Patagomaia chainko gen. et sp. nov., represented by hindlimb and pelvic elements with unambiguous therian features. We estimate Patagomaia chainko attained a body mass of 14 kg, which is considerably greater than the 5 kg maximum body mass of coeval Laurasian therians. This new discovery demonstrates that Gondwanan therian mammals acquired large body size by the Late Cretaceous, preceding their Laurasian relatives, which remained small-bodied until the beginning of the Cenozoic. Patagomaia supports the view that the Southern Hemisphere was a cradle for the evolution of modern mammalian clades, alongside non-therian extinct groups such as meridiolestidans, gondwanatherians and monotremes.